You'd write the above (or use a separate frontend app that can save to
.emt), and then use it like:

ecasound my_next_big_hit.emt -c
[...]
ecasound ('h' for help)> start

... and so on. The benefits of .emt would be:

- easier to use (hides ecasound's input, output and chain concepts);
anyone who knows how to use cakewalk, cooledit or an analog
4-track should be able to understand how the above works (perhaps
a gui is needed, but that doesn't change the concept)
- faster changing between mix-to-dsp, mix-to-file and
record-new-track modes (only one .emt file instead of
multiple ecs-files)

Negative things:

- conversion from .ecs to .emt might prove to be trickier
(.emt cannot express all chainsetup configurations),
which again means that changes made in iactive
mode are not (necessarily) stored to .emt files

Internally ecasound would convert the .emt files to chainsetup (.ecs)
files before loading. So something like: